System and method for improving a battery management and accumulator system

ABSTRACT

Various systems, methods, and apparatuses disclosed herein provide for receiving pressure data for an accumulator system, the pressure data providing an indication of a pressure in an accumulator tank of the accumulator system; receiving energy data, the energy data indicating an availability of free energy for use to charge the accumulator tank; and activating a charging source of the accumulator tank to charge the accumulator tank based on at least one of the pressure data and the energy data.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/806,463, filed Jul. 22, 2015, entitled “SYSTEM AND METHOD FORIMPROVING A BATTERY MANAGEMENT ACCUMULATOR SYSTEM,” which claims thebenefit of U.S. Provisional Patent Application Nos. 62/027,934, filedJul. 23, 2014, entitled “ELECTRIC ACCUMULATOR SYSTEM” and 62/052,593,filed Sep. 19, 2014, entitled “SYSTEM AND METHOD FOR IMPROVING A BATTERYMANAGEMENT SYSTEM,” all of which are incorporated herein by reference intheir entireties.

TECHNICAL FIELD

The present disclosure relates to accumulator systems and batterymanagement system. More particularly, the present disclosure relates toelectric powered accumulator systems and improved battery managementsystems.

BACKGROUND

Accumulator systems are used in a variety of applications. From vehiclesto industrial applications, accumulator systems are used to compress amedium, store the compressed (now pressurized) medium, and provide thepressurized medium. The pressurized medium may power one or morecomponents. For example, air may be compressed and stored. Thecompressed air may be used to power a pneumatic tool (e.g., anair-powered nail gun). In regard to a vehicle, the accumulator systemmay be used to power the air brakes (in which case, the medium is air),power an air condition system (medium may be a refrigerant), or providepower to any other type of pressurized-fluid actuated component in thevehicle. The compressor for such system is usually driven by the engine.Accordingly, when the engine is on, the compressor is running. As such,the compressor speed is tied to the engine speed. Because theaccumulator tanks may be full and/or the speed of the compressor may besub-optimal due to being linked to the engine speed, operation of theaccumulator system may lead to a loss in energy in the vehicle. This maycost vehicle operators money over the course of operation of thevehicle.

Analogously, radiator systems are used in vehicles to manage the heat ofthe engine and, in particular, to cool the engine to safe and efficientoperating temperatures. The radiator system includes a fluid circuitconfigured to transfer coolant from the radiator to the engine and backto the radiator system. Cooling fans are used with the radiator systemto cool the radiator and thereby reduce the temperature of the coolantcontained in the radiator. A conventionally employed cooling strategyoperates the cooling fan independent of the storage level of the batterysystem. Accordingly, the extra load placed on the engine to operate thecooling fan generally increases the fuel consumption and/or efficiencyof the engine.

SUMMARY

One embodiment relates to an apparatus. The apparatus includes an energygeneration module operatively coupled to one or more energy generationsources, wherein the energy module is structured to receive energy dataindicative of an availability of free energy. The apparatus alsoincludes an accumulator module communicably coupled to the energymodule, wherein the accumulator module is structured to receive pressuredata indicative of a pressure in an accumulator tank of an accumulatorsystem and facilitate charging the accumulator tank based on anindication of free energy relative to the pressure of the accumulatortank.

Another embodiment relates to a method. The method includes receiving,by a controller, pressure data for an accumulator system, the pressuredata providing an indication of a pressure in an accumulator tank of theaccumulator system; receiving, by the controller, energy data, theenergy data indicating an availability of free energy for use to chargethe accumulator tank; and activating, by the controller, a chargingsource of the accumulator tank to charge the accumulator tank based onat least one of the pressure data and the energy data.

Another embodiment relates to a system. The system includes anaccumulator system having an accumulator tank and an electric compressorstructured to charge the accumulator tank and a controller operativelyand communicably coupled to the accumulator system. The controller isstructured to: receive pressure data indicative of a pressure in theaccumulator tank; receive energy data indicative of an availability offree energy to power the electric compressor to charge the accumulatortank; and activate the electric compressor to charge the accumulatortank based on at least one of the pressure data and the energy data.

Still another embodiment relates to a method. The method includesdetermining, by a controller, a presence of an available electricalenergy quantity generated from an energy generation event; comparing, bythe controller, the available electrical energy quantity to an availableenergy capacity of a battery storage system; and responsive todetermining the available energy quantity exceeds the available energycapacity of the battery storage system, causing, by the controller, atransmission of at least a portion of the available energy quantity to aheat management system.

Yet another embodiment relates to a system. The system includes anengine; a heat management system coupled to the engine, the heatmanagement system having a fan and coolant, wherein the coolant absorbsheat from the engine, and wherein the fan is actuated based on a targettemperature of the coolant and a sensed temperature of the coolant; anda controller operatively and communicably coupled to the engine and theheat management system, the controller structured to selectively adjustthe target temperature in response to a condition of at least one of abattery and the engine to manage energy consumption by the fan.

Another embodiment relates to an apparatus. The apparatus includes aheat management module structured to receive temperature data indicativeof a temperature of coolant used in a heat management system operativelycoupled to an engine. The apparatus also includes an energy generationmodule structured to determine a presence of an available electricalenergy quantity generated from an energy generation event. The apparatusfurther includes a comparator module structured to compare the availableelectrical energy quantity to an available energy capacity of a batterystorage system. According to one embodiment, in response to thecomparison, the heat management module is structured to manage a targettemperature of the coolant to control activation of a fan in the heatmanagement system and manage energy consumption by the fan.

One embodiment relates to a method. The method includes monitoring, by acontroller, an alternator current of a battery system of a vehicle;comparing, by the controller, the monitored alternator current to acurrent limit of the alternator; receiving, by the controller, energydata, energy storage data, and current data; determining, by thecontroller, if an energy output of the battery system should be reducedbased on the alternator current, current limit, and the received energydata, energy storage data, and current data; for each engine subsystemof an engine of the vehicle, determining, by the controller, acriticality of a load from operation of the engine subsystem; for eachengine subsystem, determining, by the controller, an energy storagecapability and an energy generation capability of the engine subsystem;and determining, by the controller, a prioritization structure for theengine subsystems based on the criticality of the load and the energystorage capability and the energy generation capability of the enginesubsystems.

Still another embodiment relates to a system. The system includes apower system including a battery system structured to store energy to beused to power one or more engine subsystems of an engine of a vehicleand an energy recovery system structured to harvest energy from one ormore engine subsystems of the vehicle and to provide the energy to oneor more engine subsystems. The system also includes a controlleroperatively and communicably coupled to the power system. According toone embodiment, the controller is structured to: monitor an alternatorcurrent of the battery system; compare the monitored alternator currentto a current limit of the alternator; receive energy data, energystorage data, and current data; determine if an energy output of thebattery system should be reduced based on the alternator current,current limit, and the received energy data, energy storage data, andcurrent data; for each engine subsystem, determine a criticality of aload from operation of the engine subsystem; for each engine subsystem,determine an energy storage capability and an energy generationcapability of the engine subsystem; and determine a prioritizationstructure for the engine subsystems based on the criticality of the loadand the energy storage capability and the energy generation capabilityof the engine subsystems.

Yet another embodiment relates to an apparatus. The apparatus includes abattery module structured to manage energy to be used to power one ormore engine subsystems of an engine of a vehicle. The apparatus alsoincludes an energy module structured to harvest energy from one or moreengine subsystems of the vehicle and to provide the energy to one ormore engine subsystems. The apparatus further includes a comparatormodule communicably coupled to the battery module and the energy module.According to one embodiment, the comparator module is structured to:monitor the alternator current of the battery system; compare themonitored alternator current to a current limit of the alternator;receive energy data, energy storage data, and current data; anddetermine if an energy output of the battery system should be reducedbased on the alternator current, current limit, and the received energydata, energy storage data, and current data. The apparatus still furtherincludes a prioritization module structured to: for each enginesubsystem, determine a criticality of a load from operation of theengine subsystem; for each engine subsystem, an energy storagecapability and an energy generation capability of the engine subsystem;and determine a prioritization structure for the engine subsystems basedon the criticality of the load and the energy storage capability and theenergy generation capability of the engine subsystems.

Advantages and features of the embodiments of this disclosure willbecome more apparent from the following detailed description ofexemplary embodiments when viewed in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an engine system with a controller,according to an example embodiment.

FIG. 2 is a schematic diagram of an accumulator system, according to anexample embodiment.

FIG. 3 is schematic diagram of a heat management system, according to anexample embodiment.

FIG. 4 is a schematic diagram of the controller for the engine system ofFIG. 1, according to an example embodiment.

FIG. 5 is a schematic diagram of control logic for the accumulatorsystem of FIG. 2, according to an example embodiment.

FIG. 6 is a graph of coolant regimes used for controlling thetemperature of a coolant using a heat management system, according to anexample embodiment.

FIG. 7 is a flow diagram of a method of minimizing energy consumption inan accumulator system, according to an example embodiment.

FIG. 8 is a flow diagram of a method of energy management, according toan example embodiment.

FIG. 9 is a flow diagram of a method, for prioritizing energydistribution among vehicle subsystems, according to an exampleembodiment.

DETAILED DESCRIPTION

Following below are more detailed descriptions of various conceptsrelated to, and implementations of, methods, apparatuses, and systemsfor improving a battery management system and accumulator system. Thevarious concepts introduced above and discussed in greater detail belowmay be implemented in any of numerous ways, as the described conceptsare not limited to any particular manner of implementation. Examples ofspecific implementations and applications are provided primarily forillustrative purposes.

Referring to the figures generally, the various embodiments disclosedherein relate to a system, apparatus, and method for improving a batterymanagement system and accumulator system. With the advent of newautomotive technologies such as hybrid vehicles and the new presence ofan ample electrical energy supply on vehicle, engine accessories thathave traditionally been belt driven are becoming electrically driven.These accessories include such things as air compressors (for pneumaticdevices), air conditioning, power steering pumps, engine coolant pumps,fans, etc. Standard economic analysis usually dictates that theseelectrical generating and drive devices be sized as small as possible tokeep cost and weight down. Electrically driven accessories are generallysized such that they are able to perform their required task with enoughmargin to assure both performance at off-nominal conditions and alifetime that meets warranty requirements. The electric power supply(generally an alternator or battery) is sized to meet the typicalelectrical loads expected over an operating cycle. The electric powersupply sizing may be reduced if all or mostly all accessories areinterpreted as being critical (such as an air conditioning compressor),and if the accessory loading exceeds the power supply capacity, then inan individualistic manner, some loads may be turned off.

If the power supply is undersized to meet 100% of the electricalaccessory load 100% of the time, then a means must be provided to managethe imbalance. Traditional approaches manage the output voltage, suchthat if the voltage begins to drop due to excessive loading, then someof the loads must be turned off or disconnected. However, this is areactive method that, while never turning accessories off prematurely,always assures that the accessories must be operated for some time withinsufficient voltage in order to detect the condition. Furthermore, withthis reactive approach, it is difficult to know when it is acceptable toturn the accessories back on.

Instead, the various embodiments of the present disclosure suggests aproactive approach that estimates, predicts, and/or determines loadingof each individual assorted electrified accessory, combined with anestimate of the electrical capacity of the power supply. Thencomparisons of the electrical power supply and collective power loadsmay be made to predict or determine whether the supply meets the demand.If this prediction ever indicates insufficient supply, then one or moreaccessories in an individualistic manner may be run at a reduced powerconsumption, up to the point of being turned off completely to remedythe situation. As soon as the predicted power supply is determined tomeet or exceed the desired full accessory loading, then one or more ofthe accessories may be returned to their original power settings as thepower balance allows. This has the advantage of being proactive,substantially never subjecting the electrical accessories to “brown-out”or under-voltage type conditions, and of providing a means of knowingwhen loads may be reapplied.

Advantageously, according to the present disclosure, the loads may beprioritized and/or categorized based on their individual properties.Individual loads may be adjusted down in an analog fashion substantiallyonly if the total load exceeds the power supply. Loads may be adjustedin order of increasing priority, and may only be adjusted until thetotal load drops below the available power supply. Loads may notnecessarily be shut off completely, unless shutting off is a normaloperating mode of that device and is appropriate for current operatingconditions. Conversely, loads may also be adjusted upward if a vehiclebraking event indicates free energy is available. Each load has its ownpriority (all may be different) and a range of allowed adjustability. Inone embodiment, the controller may communicate with the controllers forthe individual primary loads (e.g. hydraulic pumps, radiator fan,pneumatic compressor, air conditioning compressor). As a result, theonly loads that are managed are those loads that are directlycontrolled, such that the individual loads will be known as the devicesperform their primary function (without requiring any kind of timeseries regression). The total loading is then tallied and compared tothe available power supply. In the event of an indicated overload,individual devices can be derated, with the derates occurring in orderof increasing priority until the overload is eliminated. This controlstrategy may provide a robust and individualistic control approach withthe loads to facilitate better management and operating characteristics.

As used herein, the term “free energy” refers to energy (e.g.,electricity) that is otherwise lost. Free energy may be recovered usingan energy recovery system (e.g., from power system 30). In one example,the energy recovery system is structured as a regenerative brakingsystem. In the regenerative braking configuration, as an operator of avehicle applies the brake pedal, an electric motor reverses directionsand generates electricity. This electricity may be stored in one or morebatteries and used to power one or more components. Here, theelectricity generated by the regenerative braking system is provided toan electric compressor (i.e., the electric motor powering thecompressor) and/or a heat management system (i.e., a fan to cool aradiator). In comparison, non-free energy refers to energy expendituresfor a specific purpose. For example, non-free energy would includeutilizing a fuel to power an internal combustion engine to power anengine accessory. Here, although fuel may be used to power the internalcombustion engine, the free energy (from the regenerative brakingsystem) is generated as a by-product of operation of the internalcombustion engine. This is energy that would otherwise be lost as, forexample, heat.

Referring now to FIG. 1, a schematic diagram of an engine system 10 witha controller 300 is shown, according to an example embodiment. Accordingto one embodiment, the engine system 10 is embodied within a vehicle.The vehicle may include an on-road or an off-road vehicle including, butnot limited to, line-haul trucks, mid-range trucks (e.g., pick-up truck,etc.), sedans, coupes, tanks, airplanes, boats, and any other type ofvehicle. In some embodiments, the engine system 10 may be implemented instationary devices, such as a power generator. All such variations areintended to fall within the spirit and scope of the present disclosure.Further, while FIG. 1 depicts the engine system 10 as including aninternal combustion engine 20, the engine system 10 may be powered byanother type of power source. For example, the engine system 10 may be ahybrid system or an internal combustion engine powered system as shown.These and other features of the present disclosure are described morefully herein below.

By way of example, the engine system 10 may typically include apowertrain system. The powertrain system includes an engine 20. Thepowertrain system may include any type of components typically includedin powertrain systems. For example, the powertrain system may alsoinclude, but is not limited to, a transmission, a drive shaft, adifferential, and a final drive. As a brief overview, in a vehicleimplementation, the engine 20 receives a chemical energy input (e.g., afuel such as gasoline, diesel, natural gas, propane, etc.) and combuststhe fuel to generate mechanical energy, in the form of a rotatingcrankshaft. The transmission receives the rotating crankshaft andmanipulates the speed of the crankshaft (i.e., the enginerevolutions-per-minute (RPM), etc.) to affect a desired drive shaftspeed. The rotating drive shaft is received by the differential, whichprovides the rotational energy of the drive shaft to the final drive.The final drive then propels or moves the vehicle.

The engine 20 may be structured as any internal combustion engine (e.g.,compression-ignition, spark-ignition, etc.), such that it may be poweredby any fuel type (e.g., diesel, ethanol, gasoline, etc.). Similarly, thetransmission may be structured as any type of transmission, such as acontinuous variable transmission, a manual transmission, an automatictransmission, an automatic-manual transmission, a dual clutchtransmission, etc. Accordingly, as transmissions vary from geared tocontinuous configurations (e.g., continuous variable transmissions,etc.), the transmission can include a variety of settings (gears, for ageared transmission) that affect different output speeds based on theengine speed. Like the engine 20 and the transmission, the drive shaft,differential, and final drive may be structured in any configurationdependent on the application (e.g., the final drive is structured aswheels in an automotive application and a propeller in an airplane orboat application, etc.). Further, the drive shaft may be structured asany type of drive shaft including, but not limited to, a one-piece, atwo-piece, and a slip-in-tube driveshaft based on the application.

As shown in FIG. 1, the engine system 10 includes a power system 30, abraking system 40, and engine subsystems 50. The power system 30 mayinclude a battery system 32 and an energy recovery system 34. Thebattery system 32 may include one or more batteries. The battery system32 is configured to store energy to be used to power one or morecomponents of the engine subsystems 50. The energy recovery system 34 isstructured to generate energy that would otherwise be lost duringoperation of the engine system 10 (e.g., in the form of friction, heat,etc.). In one embodiment, the energy generated by the energy recoverysystem 34 is stored in the battery system 32. In other embodiments, theenergy recovery system 34 provides the generated energy directly to oneor more components of the engine subsystems 50, bypassing the batterysystem 32. In still other embodiments, the energy recovery system 34provides the generated energy to at least one of the battery system 32and the engine subsystems 50. According to an example embodiment, theenergy recovery system 34 is structured as an regenerative brakingsystem. As shown in FIG. 1, the braking system 40 is coupled to theenergy recovery system 34. The energy recovery system 34 is structuredto harvest energy from the braking system 40 during braking events andproduce electrical energy therefrom. Thus, the power system 30 isstructured to harvest energy from the engine 20 that would otherwise belost during operation of the engine system 10.

The engine subsystems 50 may be directly or indirectly coupled to theengine 20. For example, some of the engine subsystems 50 may be fluidlycoupled to the engine 20 (e.g., an exhaust aftertreatment system, a heatmanagement system, etc.), while other engine subsystems 50 may beindirectly powered from energy initially provided by the engine 20(e.g., electric subsystems that are powered by the power system 30,etc.). The engine subsystems 50 may include both electrically-poweredaccessories and engine driven accessories, as well any other type ofsubsystem in the engine system 10. For example, the engine subsystems 50may include an exhaust aftertreatment system. The exhaust aftertreatmentsystem may include any component used to reduce exhaust emissions (e.g.,diesel exhaust emissions, gas exhaust emissions, etc.), such as aselective catalytic reduction catalyst, a diesel oxidation catalyst, adiesel particulate filter, a diesel exhaust fluid doser with a supply ofdiesel exhaust fluid, and a plurality of sensors for monitoring theaftertreatment system (e.g., a NOx sensor, etc.). Furthermore, variousaccessories may include, but are not limited to, air compressors (forpneumatic devices), air conditioning systems, power steering pumps,engine coolant systems and pumps, fans, and the like.

According to the example embodiment shown in FIG. 1, the enginesubsystems 50 include an accumulator system 100 and a heat managementsystem 200. In other embodiments, the engine subsystems 50 may includedifferent or additional subsystems, such as HVAC systems and powersteering pumps. Therefore, the accumulator system 100 and the heatmanagement system 200 are non-limiting examples of possible enginesubsystems 50. The accumulator system 100 may include an electric aircompressor that provides compressed air to an air tank, which is used topower one or more pneumatic devices of the engine system 10 (e.g., airbrakes, power steering, etc.).

Referring still to FIG. 1, the engine system 10 may include one or moresensors 340 communicably coupled to one or more components of the enginesystem 10, the controller 300, and an operator input/output (I/O) device330. Communication between and among the components of the engine system10 may be via any number of wired or wireless connections. For example,a wired connection may include a serial cable, a fiber optic cable, aCAT5 cable, or any other form of wired connection. In comparison, awireless connection may include the Internet, Wi-Fi, cellular, radio,etc. In one embodiment, a controller area network (CAN) bus provides theexchange of signals, information, and/or data. The CAN bus includes anynumber of wired and wireless connections. Because the controller 300 iscommunicably coupled to the systems and components in the engine system10 of FIG. 1, the controller 300 may receive data from one or more ofthe components shown in FIG. 1. For example, the data may includepressure data, temperature data, energy data, energy storage data,and/or current data acquired via one or more of the sensors 340. Asanother example, the data may include an input from operator I/O device330. As described more fully herein, with this data, the controller 300may prioritize which of the engine subsystems 50, if any, receive energyfrom at least one of the battery system 32 and the energy recoverysystem 34 of the power system 30.

The operator I/O device 330 enables an operator of the engine system 10to communicate with the engine system 10 and the controller 300. Forexample, the operator I/O device 330 may include, but is not limited to,an interactive display, a touchscreen device, one or more buttons andswitches, voice command receivers, etc. The operator of the enginesystem 10 may also use the operator I/O device 330 to define variouslimits and a threshold for the operation of the engine 20, the powersystem 30, and/or the engine subsystems 50, which are described morefully herein.

As the components of FIG. 1 are shown to be embodied in the enginesystem 10, in one embodiment the controller 300 may be embodied as anadd-on to an electronic control module (ECM). In some embodiments, thecontroller 300 may be a stand-alone tool that performs all required datalogging, data tracking, data analysis, etc. needed to monitor theoperation of the engine system 10. In some embodiments, the controller300 is included in the ECM of a vehicle. The ECM may include atransmission control unit and any other vehicle control unit (e.g.,exhaust aftertreatment control unit, powertrain control module, enginecontrol module, etc.). In an alternative embodiment, the controller 300is web based, server based, and/or application based (e.g., a smartphoneapp, a controller on the internet, etc.). The structure and function ofthe controller 300 is further described in regard to FIG. 4.

Referring now to FIG. 2, the function and structure of the accumulatorsystem 100 are shown according to one embodiment. As shown in FIG. 2,the accumulator system 100 includes a compressor 110, a motor 120, adryer 130, an accumulator tank 140, a pressure sensor 342, and agovernor 160. The compressor 110 receives a medium 105 (e.g., air,refrigerant, etc.). The motor 120 powers the compressor 110 to compressthe medium 105. Collectively, the motor 120 and compressor 110 form anelectric compressor. The compressed medium is then provided to a dryer130. The dryer 130 is structured to substantially remove the moisturefrom the compressed medium. The accumulator system 100 may include morethan one dryer 130 and the dryers may be of different types. As such,the dryer 130 may include, but is not limited to, a refrigerated dryer,a deliquescent dryer, a membrane dryer, etc. After drying, the medium105 is provided to the accumulator tank 140. The accumulator tank 140stores the dried, compressed medium 105 and may provide it as needed.For example, the accumulator tank 140 may provide the pressurized medium105 to operate a pump (e.g., a wheel chair lift in a vehicle, an airbrake system, etc.). One or more pressure sensors 342 measure thepressure in the accumulator tank 140 and provide this pressure data tothe controller 300. The governor 160 is structured to purge the dryer130 and/or the accumulator tank 140. In this regard, the governor 160may function as a backup pressure relief actuator to the pressure sensor342.

As mentioned above, the governor 160 enables a pressure release in thedryer 130 and/or the accumulator tank 140. Accordingly, the governor 160may have various pressure settings, which trigger the opening of a valvesuch that the high pressure contents in the dryer 130 and/or theaccumulator tank 140 may be released and the pressure lowered in thedryer 130 and/or the accumulator tank 140. The governor 160 may bestructured as a mechanical governor, release valve, check valve, and thelike. In some embodiments, the governor 160 may be structured as asolenoid valve. In one embodiment, the controller 300 may activate thegovernor 160 based on the pressure data. Alternatively, the pressuredata signal may be provided directly to the governor 160 to enableautomatic activation. In either configuration—mechanical governor orsolenoid governor—the governor 160 functions to purge the dryer 130and/or the accumulator tank 140. This may occur when the pressurereaches a certain level (e.g., cut-out pressure) and the compressor 110is turned off.

The compressor 110 is structure-dependent on the application.Accordingly, the compressor 110 may be embodied as a reciprocatingcompressor, a rotary screw compressor, a rotary centrifugal compressor,variations thereof, and any other type of compressor based on theapplication. Similarly, the size (pressure output, medium flow output,horsepower) of the compressor 110 is dependent on the application. Forexample, a truck may utilize a compressor with a maximum pressure outputof 150 pounds-per-square-inch (“PSI”), whereas a compressor in abuilding may require a substantially greater pressure output.

The compressor 110 is powered by the motor 120 rather than the engine20. Thus, the compressor 110 speed is not tied to the engine speed. Thisallows the compressor 110 to operate independent of the engine 20, whichenables optimum performance (e.g., energy savings from not constantlyoperating the compressor 110 and a greater efficiency by running thecompressor 110 at the necessary speed rather than the speed of theengine 20, etc.). Because the compressor 110 is not related to theengine 20, the compressor 110 may be powered on/off by the controller300 via activation/deactivation of the motor 120 despite continuousoperation of the engine 20. This enables a relatively greater amount ofenergy savings and efficiency.

The motor 120 receives power from the power system 30. In oneembodiment, the battery system 32 provides energy to the motor 120 topower the compressor 110. In other embodiments, when the vehicle isslowed down by the braking system 40, the motor 120 may receive freeenergy captured by the energy recovery system 34 of the power system 30.For example, an operator of the vehicle may apply the brakes, whichcauses the generation of electricity by the energy recovery system 34.Among other destinations, this electricity may be directly provided tothe motor 120 to power the compressor 110 (and other components) and/orstored in the battery system 32. Although described as separatecomponents (the motor 120 and the energy recovery system 34), the motor120 may perform both functions (i.e., a unitary component). Hence, themotor 120 may operating in a “motoring” mode where power is provided to,e.g., the compressor 110, and a “generating” mode, where electricity isgenerated from a reversed direction (relative to the “motoring” rotationdirection) of operation of the motor 120.

As with the compressor 110, the accumulator tank 140 may be structured(e.g., size, such as five gallons, etc.) based on the application of thesystem. Similarly, more than one accumulator tank 140 with correspondingpressure sensors 342 may be utilized. The pressure sensor 342 obtainspressure data regarding the accumulator tank 140. More than one pressuresensor 342 may be used per tank 140 and the pressure sensor 342 may takea wide variety of forms, such as a differential pressure sensor, asealed pressure sensor, a vacuum pressure sensor, a gauge pressure, etc.The pressure data corresponds with the pressure in the accumulatortank(s) 140. This pressure corresponds with a current capacity of thetank(s) 140 (i.e., less pressure equates to a relatively less full tank140). The pressure data is provided to the controller 300.

As a brief overview, the controller 300 receives data regarding thepressure in the accumulator tank 140 and data regarding operation of theengine system 10. The engine operation data provides an indication ofwhen regenerative braking is occurring. The controller 300 utilizes thefree energy from regenerative braking to power the compressor 110 andfill the accumulator tank 140. Because the energy from regenerativebraking is not always available, the controller 300 may include anadjustable tank pressure setting. The adjustable tank pressure settingmay function like a cut-out setting for the compressor 110. If thepressure in the accumulator tank drops below a predetermined minimum,the controller 300 will activate the compressor 110. Because no freeenergy is available, the compressor 110 is driven by non-free energy(e.g., from the battery system 32). Rather than continuing to use thisnon-free energy to fill the accumulator tank 140 to the cut-outpressure, the adjustable tank pressure setting acts as a trigger to thecontroller 300 to shut the compressor 110 down. Thus, the pressuresetting is below the cut-out setting. Although the accumulator tank 140may not be full, the pressure in the accumulator tank 140 is above theminimum level and energy was conserved by not running the compressor 110until the cut-out pressure in the accumulator tank 140 was reached.Accordingly, in some embodiments, the example accumulator systems of thepresent disclosure provide a method of minimizing the amount of non-freeenergy used in an accumulator system.

Because the accumulator tank 140 can vary based on the application, socan the cut-in pressure and the cut-out pressure. The cut-in pressurerefers to the minimum pressure allowed in the accumulator tank 140. Whenthe pressure in the accumulator tank 140 is at or below the cut-inpressure, the controller 300 activates the compressor 110 (i.e., motor120) to refill the accumulator tank 140. The cut-out pressure refers tothe maximum pressure allowed in the accumulator tank 140. At the cut-outpressure, the controller 300 deactivates the compressor 110 to preventover-pressurizing the accumulator tank 140. Both the cut-in and cut-outpressure may be preset using the controller 300 and may vary based onthe application.

Referring now to FIG. 3, the function and structure of the heatmanagement system 200 are shown according to one embodiment. The heatmanagement system 200 for the engine 20 includes a radiator 202 and acooling fan 204. The cooling fan 204 may include an electrical coolingfan or a fan mechanically connected to an engine, but electricallyoperated or controlled, for example via an electrically operated clutch.The radiator 202 is fluidly coupled to the engine 20 to pass coolantfrom the radiator 202 to the engine 20 and back to the radiator 202. Thecoolant absorbs heat from the engine 20 as the coolant passes throughthe engine 20. Flow of the coolant from the radiator 202 to the internalcombustion engine 20 may be controlled via one or more thermostatsconfigured to open once the temperature of the engine 20 reaches acertain temperature. The heated coolant returns to the radiator 202 fromthe engine 20, to be cooled in the radiator 202.

According to an example embodiment, the cooling fan 204 blows air acrossthe radiator 202 to increase the cooling of the radiator 202 aswarranted. The timing (period of actuation) and speed of the cooling fan204 are controlled in response to the temperature of the coolant andhence required cooling of the coolant. The required cooling of thecoolant may be sensed by one or more temperature sensors 344, such as athermocouple, positioned in the radiator 202 or along the fluid circuitfrom the engine 20 to the radiator 202. More specifically, thecontroller 300 is configured to control the operation of the cooling fan204 based on sensed conditions of the coolant and/or based on one ormore other parameters including, but not limited to, energy generation,battery capacity, energy demands of other electrical components of theengine system 10 (e.g., HVAC requests, etc.).

As shown in FIG. 3, the cooling fan 204 may receive electrical energyfrom at least one of the battery system 32 and the energy recoverysystem 34 of the power system 30. The controller 300 is structured tocontrol which of the battery system 32 and the energy recovery system 34provides the electrical energy to the cooling fan 204. The controller300 make these determinations and in what quantities based on variousoperating parameters of the engine system 10 and the components of theengine system 10 (e.g., the energy recovery system 34, the accumulatorsystem 100, the heat management system 200, etc.).

Referring now to FIG. 4, the function and structure of the controller300 are shown according to one embodiment. The controller 300 is shownto include a processing circuit 302 including a processor 304 and amemory 306. The processor 304 may be implemented as a general-purposeprocessor, an application specific integrated circuit (ASIC), one ormore field programmable gate arrays (FPGAs), a digital signal processor(DSP), a group of processing components, or other suitable electronicprocessing components. The one or more memory devices 306 (e.g., NVRAM,RAM, ROM, Flash Memory, hard disk storage, etc.) may store data and/orcomputer code for facilitating the various processes described herein.Thus, the one or more memory devices 306 may be communicably connectedto the processor 304 and provide computer code or instructions to theprocessor 304 for executing the processes described in regard to thecontroller 300 herein. Moreover, the one or more memory devices 306 maybe or include tangible, non-transient volatile memory or non-volatilememory. Accordingly, the one or more memory devices 306 may includedatabase components, object code components, script components, or anyother type of information structure for supporting the variousactivities and information structures described herein.

The memory 306 is shown to include various modules for completing theactivities described herein. More particularly, the memory 306 includesan energy generation module 310, a battery module 312, an engine module314, an accumulator module 316, a heat management module 318, a demandmodule 320, a comparator module 322, and a prioritization module 324.The modules 310-324 are structured to control the energy supply tovarious engine subsystems 50 based on the operation of the engine system10 and the electrical energy available (e.g., the stored energy in thebattery system 32, the amount of energy being generated by the energyrecovery system 34, etc.). While various modules with particularfunctionality are shown in FIG. 4, it should be understood that thecontroller 300 and memory 306 may include any number of modules forcompleting the functions described herein. For example, the activitiesof multiple modules may be combined as a single module, as additionalmodules with additional functionality may be included, etc. Further, itshould be understood that the controller 300 may further control otheractivity beyond the scope of the present disclosure.

Example and non-limiting module implementation elements include sensorsproviding any value determined herein, sensors providing any value thatis a precursor to a value determined herein, datalink and/or networkhardware including communication chips, oscillating crystals,communication links, cables, twisted pair wiring, coaxial wiring,shielded wiring, transmitters, receivers, and/or transceivers, logiccircuits, hard-wired logic circuits, reconfigurable logic circuits in aparticular non-transient state configured according to the modulespecification, any actuator including at least an electrical, hydraulic,or pneumatic actuator, a solenoid, an op-amp, analog control elements(springs, filters, integrators, adders, dividers, gain elements), and/ordigital control elements.

Certain operations of the controller 300 described herein includeoperations to interpret and/or to determine one or more parameters.Interpreting or determining, as utilized herein, includes receivingvalues by any method known in the art, including at least receivingvalues from a datalink or network communication, receiving an electronicsignal (e.g. a voltage, frequency, current, or PWM signal) indicative ofthe value, receiving a computer generated parameter indicative of thevalue, reading the value from a memory location on a non-transientcomputer readable storage medium, receiving the value as a run-timeparameter by any means known in the art, and/or by receiving a value bywhich the interpreted parameter can be calculated, and/or by referencinga default value that is interpreted to be the parameter value.

The energy generation module 310 is structured to determine energygeneration events and quantities of energy generated during such eventsby components such as the braking system 40 and the energy recoverysystem 34. The energy generation module 310 may be communicably coupledto one or more sensors, such as the sensors 340, configured to acquire,gather, and/or receive energy data 350. As such, the energy generationmodule 310 may include communication circuitry (e.g., relays, wiring,network interfaces, circuits, etc.) that facilitate the exchange ofinformation, data, values, non-transient signals, etc. between and amongthe energy generation module 310 and the one or more sensors 340. Theenergy data 350 may provide an indication of the type of energyavailable: free energy or non-free energy. The energy data 350 mayinclude an indication of an accelerator pedal position, a vehicle speed,a brake pedal position, an engine fueling rate, an amount of electricalenergy generated, and any other data point that provides an indicationof the type of energy available. In some embodiments, the energygeneration module 310 may include or be communicably coupled to theenergy recovery system 34 as a means for controlling operation of theenergy recovery system 34. As such, the energy generation module 310 maybe structured to control where the energy generated by the energyrecovery system 34 is directed. For example, the energy generationmodule 310 may cause the energy recovery system 34 to provide thegenerated energy to the battery system 32, one or more of the enginesubsystems 50, or a combination thereof.

The battery module 312 is structured to determine the available energystorage capacity of the battery system 32. The battery module 312 may becommunicably coupled to one or more sensors, such as the sensors 340,configured to acquire energy storage data 352 and/or current data 360.As such, the battery module 312 may include communication circuitry(e.g., relays, wiring, network interfaces, circuits, etc.) thatfacilitate the exchange of information, data, values, non-transientsignals, etc. between and among the battery module 312 and the one ormore sensors 340. The energy storage data 350 may provide an indicationof the amount of energy stored within the battery system 32. In someembodiments, the battery module 312 may include or be communicablycoupled to the battery system 32 as a means for controlling operation ofthe battery system 32. As such, the battery module 312 may be structuredto control the timing of and the amount of the stored energy within thebattery system 32 that is supplied to one or more of the enginesubsystems 50. The current data 360 may provide an indication of acurrent output of the power system 30 (e.g., the battery system 32,etc.). The battery module 312 may be structured to monitor the currentoutput of the battery system 32. Typically, the supply limitation thatcauses output voltage of electrical power system to falter and drop is acurrent limit of the electrical power system. For this reason, thebattery module 312 is structured to monitor the output current of thebattery system 32.

The engine module 314 is structured to receive engine data 354indicative at least one operating characteristic of the engine 20. Theengine module 314 may be communicably coupled to one or more sensors,such as the sensors 340, configured to acquire the engine data 350. Assuch, the engine module 314 may include communication circuitry (e.g.,relays, wiring, network interfaces, circuits, etc.) that facilitate theexchange of information, data, values, non-transient signals, etc.between and among the engine module 314 and the one or more sensors 340.The at least one engine characteristic may include an engine speed, anengine temperature, a throttle position, an amount of fueling, a poweroutput, and/or any other engine characteristics that indicate a currentdemand required to be met by the engine 20. In some embodiments, theengine module 314 may include or be communicably coupled to the engine20 as a means for controlling operation of the engine 20.

The accumulator module 316 is structured to receive pressure data 356indicative of a pressure in the accumulator tank 140. The accumulatormodule 316 may be communicably coupled to one or more sensors, such asthe pressure sensors 342, configured to acquire the pressure data 356.As such, the accumulator module 316 may include communication circuitry(e.g., relays, wiring, network interfaces, circuits, etc.) thatfacilitate the exchange of information, data, values, non-transientsignals, etc. between and among the engine module 314 and the one ormore pressure sensors 342. The pressure data 356 may be receivedcontinuously, periodically, and/or based on operation of one or morecomponents (e.g., the compressor 110, etc.).

In some embodiments, the accumulator module 316 may include or becommunicably coupled to the accumulator system 100 as a means forcontrolling operation of the motor 120 to operator the compressor 110.In regard to the pressure data 356, the pressure data 356 may indicatethat the pressure in the accumulator tank 140 is at or below a minimumpressure setting, at or above a maximum allowed pressure, or somewherein between. When the pressure in the accumulator tank 140 is at or belowa minimum pressure setting, the accumulator module 316 may activate thecharging or facilitate the activation of a charging source, such as thecompressor 110, for the accumulator tank 140. This is because one ormore components in the engine system 10 may need at least the minimumpressure in the accumulator tank 140 to function. When the pressure isat or above the maximum allowed pressure, the accumulator module 316deactivates the compressor 110 to prevent over-pressurizing theaccumulator tank(s) 140. When pressure in the accumulator tank 140 issomewhere in between the minimum and maximum pressure or less than theminimum pressure setting, the energy data 350, the energy storage data352, the pressure data 356, and the accumulator tank pressure settingmay influence the charging of the accumulator tank(s) 140.

The heat management module 318 is structured to receive temperature data358 indicative of a temperature of at least one of the radiator 202, theengine 20, and the coolant. The heat management module 318 may becommunicably coupled to one or more sensors, such as the temperaturesensor 344, configured to acquire the temperature data 358. As such, theheat management module 318 may include communication circuitry (e.g.,relays, wiring, network interfaces, circuits, etc.) that facilitate theexchange of information, data, values, non-transient signals, etc.between and among the heat management module 318 and the one or moretemperature sensors 344. The temperature data 358 may be receivedcontinuously, periodically, and/or based on operation of one or morecomponents (e.g., the cooling fan 204, etc.). In some embodiments, theheat management module 318 may include or be communicably coupled to theheat management system 200 as a means for controlling operation of thecooling fan 204 to modulate the target temperature of the coolant in theradiator 202.

The demand module 320 is configured to determine the energy demands ofthe various engine subsystems 50 based on the operation of the enginesystem 10. As such, the demand module 320 may include communicationcircuitry (e.g., relays, wiring, network interfaces, circuits, etc.)that facilitate the exchange of information, data, values, non-transientsignals, etc. between and among the demand module 320, the engine module314, the accumulator module 316, and the heat management module 318. Forexample, the demand module 320 may determine that the accumulator system100 requires a supply of energy to run the compressor 110 to increasethe pressure within the accumulator tank above the minimum pressuresetting. In another example, the demand module 320 may determine thatthe heat management system 200 requires a supply of energy to run thecooling fan 204 to decrease the temperature of the coolant, andconsequently the engine 20.

The comparator module 322 is structured to compare the various data anddeterminations made by the other modules 310-320 to make determinationson energy supplied to the engine subsystems 50 (e.g., an amount ofenergy supplied by the battery system 32, an amount of energy stored inthe battery system 32 from the energy recovery system 34 and an amountprovided to the engine subsystems from the energy recovery system 34,etc.). As such, the comparator module 322 may include communicationcircuitry (e.g., relays, wiring, network interfaces, circuits, etc.)that facilitate the exchange of information, data, values, non-transientsignals, etc. between and among the comparator module 322, the demandmodule 320, the energy generation module 310, the battery module 312,the engine module 314, the accumulator module 316, and the heatmanagement module 318. In one embodiment, the comparator module 322 isstructured to compare the energy being generated by the energy recoverysystem 34 to the available energy capacity of the battery system 32.Based on the comparison, the comparator module 322 may determine whichof the battery system 32, the energy recovery system 34, or acombination thereof should supply energy to the engine subsystems 50. Insome embodiments, the comparator module 322 further factors in theexisting demands of the engine subsystems 50 to determine how muchenergy should be provided to each of the engine subsystems 50. In someembodiments, the comparator module 322 is structured to determinewhether one or more of the engine subsystems 50 should be supplieddecreased amounts of energy or turned off completely in response to themeasured current (e.g., indicated by the current data 360, etc.) of thebattery system 32 approaching a prescribed limit (i.e., a currentthreshold).

The accumulator module 316 and the heat management module 318 maycontrol the accumulator system 100 and the heat management system 200according to the determinations made by the comparator module 322.Referring also to FIG. 5, example control logic for an implementation ofthe accumulator module 316 and the comparator module 322 with theaccumulator system 100 is shown according to an example embodiment. Moreparticularly, FIG. 5 illustrates the control of a pressure in theaccumulator tank 140 using the accumulator module 316 and the comparatormodule 322. The example control logic is intended for use in a vehicle.More particularly, the example control logic is intended for use in avehicle with air brakes (e.g., a semi-tractor truck). The examplecontrol logic may be embodied in the accumulator module 316 and/or thecomparator module 322.

Accordingly, the comparator module 322 receives the pressure data 356(input 501) and the energy data 350 (input 502). Input 502 may include,for example, the position of the acceleration pedal of the vehicle andthe current vehicle speed. As described above, from the energy data 350,the comparator module 322 determines the availability of free energy atblock 503. In this example, the adjustable pressure setting is 120 PSI,the minimum pressure setting is 105 PSI, and the maximum allowedpressure in the tank is 125 PSI. If the tank pressure is below 105 PSI,the accumulator module 316 provides a command (output 504) to turn onthe electric compressor 110 by using fuel (non-free energy) to chargethe tank to 120 PSI. When the tank pressure reaches 125 PSI, theaccumulator module 316 provides a command to deactivate the electriccompressor (output 504).

According to this example, the controller 300 uses the following presetstandards to determine the availability of free energy based on thepressure data. If the tank pressure is less than 125 PSI, theaccelerator pedal position is less than one-percent, and the vehiclespeed is greater than one mile-per-hour, the controller 300 provides acommand (output 404) to activate the electric compressor to charge theair tank. This command may be provided until the maximum allowedpressure in the tank is reached or the availability of free energyceases. With the above example conditions, the accelerator pedal isbarely depressed (if at all), but the vehicle is moving. Because theaccelerator pedal is barely depressed, engine fueling is minimized.Thus, application of the regenerative braking system may be in use(accelerator pedal is not being used), such that free energy isavailable. Accordingly, the controller 300 provides a command toactivate the electric compressor.

Referring now to FIG. 6, a graph of coolant regimes used for energymanagement systems in accordance with example embodiments is shown. Moreparticularly, FIG. 6 illustrates the control of the temperature of acoolant using the heat management module 318 and the comparator module322. During periods of time when extra energy would be required to runthe cooling fan 204 because the coolant temperature is above a nominalcoolant temperature target 601, the nominal coolant temperature target601 is increased toward an upper limit threshold 602. This upper limitthreshold 602 could be as high as 260 degree F. for some embodiments. Ifthe coolant temperature reaches the upper limit threshold 602, thecooling fan 204 engages. If the coolant temperature, for example assensed by the temperature sensor 344, does not reach the upper limitthreshold 602, then the cooling fan 204 comes on at the nextregenerative braking opportunity. During periods of time when thecoolant temperature is at the nominal coolant temperature target 601,but braking energy from a regenerative braking event is available thatis not storable in the battery system 32 (for insufficient capacity inthe battery system 32), the nominal coolant temperature target 601 isdecreased towards a coolant temperature lower limit 603. Decreasing thenominal coolant temperature target 601 towards the coolant temperaturelower limit 603 causes the cooling fan 204 to run and thereby drop thecoolant temperature below the nominal coolant temperature target 601 toallow for decreased fan requirements for cooling during other operatingtimes.

Referring again to FIG. 4, the prioritization module 324 is structuredto determine which of the engine subsystems 50 should receive energybased on load criticality and storage capability of the various enginesubsystems 50 and the battery system 32. As such, the prioritizationmodule 324 may include communication circuitry (e.g., relays, wiring,network interfaces, circuits, etc.) that facilitate the exchange ofinformation, data, values, non-transient signals, etc. between and amongthe prioritization module 324, the comparator module 322, the enginemodule 314, the accumulator module 316, and the heat management module318. It would be desirable to have a backup or second-tiered approachfor powering various vehicle subsystems if the battery management systemas described in the present disclosure fails to detect an overloadedsupply for any reason. For example, some vehicle subsystems that requireloads are subject to operator selection and cannot be turned on an offby the controller 300 (e.g., HVAC fans, headlights, window defoggers,cigarette lighters, etc.). The prioritization module 324 may beconfigured to manage a backup power system to account for such vehiclesubsystems, to avoid a brown-out condition.

The prioritization module 324 is structured to determine aprioritization structure for the engine subsystems 50. The reduction ofan accessory load does not need to be done uniformly, as there are loadcharacteristics that may suggest a “natural” prioritization structure,allowing some accessory loads to be maintained while other accessoryloads are reduced. The first priority may be the criticality of theload. For example, the engine subsystems 50 that are critical to propervehicle operation (e.g., a power steering system, etc.) should not becompromised and therefore are not good candidates to be manipulated aspart of the load management. A second priority may be the means ofenergy storage associated with the load. Many accessory loads on anengine or vehicle perform a function that represents some form of energytranslation, which have a degree of energy storage capability. Energystorage capability provides the means to offset reduced operation withincreased operation at some point in the future. For example, an aircompressor for vehicle pneumatics converts mechanical energy intopneumatic energy usually stored in an air tank (e.g., the accumulatorsystem 100, etc.); reduced compressor operation now can be offset byharder operation in the future, relying on the stored compressed air tobridge the temporary gap. Similarly, engine or motor cooling systemregulates the thermal energy stored in the system; reduced coolingoperation now can be offset by harder operation in the future so long asthe system can tolerate the temporary increase in thermal energy (e.g.,the heat management system 200, etc.). As another example, powersteering has no storage capability, so is not a good candidate foraccessory load adjustment. The prioritization module 324 uses thepriorities to determine which accessory loads should be adjusted if anelectrical overloading situation arises.

The prioritization module 324 is structured to prioritize and/orcategorize the loads based on their individual properties. Theprioritization structure determined by the prioritization module 324 maybe used to adjust down individual loads in an analog fashionsubstantially only if the total load exceeds what is able to be providedby the battery system 32 and/or the energy recovery system 34. The loadsmay be adjusted in order of increasing priority determined by theprioritization module 324, and may only be adjusted until the total loaddrops below the available power supply (e.g., the stored energy in thebattery system 32 and the generated energy by the energy recovery system34, etc.). Loads may not necessarily be shut off completely, unlessshutting off is a normal operating mode of that device and isappropriate for current operating conditions. Conversely, loads may alsobe adjusted upward if an energy generation event (e.g., a vehiclebraking event, etc.) indicates free energy is available. Each load hasits own priority (all may be different) and a range of allowedadjustability determined by the prioritization module 324. In oneembodiment, the prioritization module 324 may communicate with thecontrollers for the individual primary loads (e.g. hydraulic pumps,radiator fan, pneumatic compressor, air conditioning compressor, theaccumulator system 100, the heat management system 200, etc.). The totalloading is tallied and compared to the available power supply by thecomparator module 322. In the event of an indicated overload, individualengine subsystems 50 can be derated, with the derates occurring in orderof increasing priority determined by the prioritization module 324 untilthe overload is eliminated. This may provide a robust andindividualistic control approach with the loads to facilitate bettermanagement and operating characteristics of the engine system 10,specifically efficiently of the engine 20, the power system 30, and/orthe engine subsystems 50.

Referring now to FIG. 7, a method 700 of minimizing energy consumptionin an accumulator system 100 is shown according to an exampleembodiment. Method 700 may be implemented with the controller 300 ofFIG. 1 and the accumulator system 100 of FIG. 2. Accordingly, method 700is described with regards to FIGS. 1-2. At the outset, the accumulatortank(s) 140 of the accumulator system 100 may have preset cut-in andcut-out pressures. However, the cut-in and cut-out pressures may beadjusted by a user of the system via the controller 300. In eitherconfiguration, method 700 begins at block 701. At block 701, thecontroller 300 receives pressure data for an accumulator system (e.g.,the accumulator system 100, etc.). The pressure data may be obtained bya pressure sensor (e.g., the pressure sensor 342, etc.) and correspondwith a pressure level in each one of the one or more accumulator tanks(e.g., the accumulator tank 140, etc.). The pressure data may bereceived continuously, periodically, and/or based on operation of one ormore components (e.g., the compressor 110, etc.).

As mentioned above in regard to FIG. 1, in some embodiments, thecontroller 300 may receive a pressure setting for the accumulator tank(block 702). The pressure setting controls the amount of non-free energyused to charge (fill) the accumulator tank(s). In one embodiment, thepressure setting is less than a cut-out setting (i.e., maximum allowedpressure) for the accumulator tank.

At block 703, the controller 300 receives energy data. The energy dataprovides an indication of the type of energy available: free energy ornon-free energy. As described in regard to block 704, knowing the typeof energy available enables the controller 300 to control activation ofthe compressor (e.g., via the motor 120, etc.) to minimize energyconsumption. The energy data may include an indication of an acceleratorpedal position, a vehicle speed, a brake pedal position, an enginefueling rate, and any other data point that provides an indication ofthe type of energy available. Sensors may be communicably coupled to thecontroller 300 and any other component within the vehicle (e.g., powersystem 30, etc.). Accordingly, the sensors may provide the controller300 with the energy data by monitoring/taking measurements from one ormore components in the vehicle or engine system.

As an example, a position sensor may be mounted on the brake pedal in avehicle and the power system may be configured as a regenerative brakingsystem (e.g., the braking system 40, etc.). The position sensor providesdata to the controller 300 regarding the position of the brake pedal.Accordingly, the controller 300 may determine when the brake pedal isdepressed. In this example, when the brake pedal is depressed,regenerative braking is occurring. As such, the controller 300determines that free energy is available. As soon as the sensor providesdata that the brake pedal is no longer depressed, the controller 300 maydetermine that free energy is no longer available. This information isused to provide the command described in block 704. Although describedin regard to the brake pedal position, the same type of sensor readingmay be provided in regard to the accelerator pedal position. Similarly,a rapid decrease in vehicle speed may indicate the occurrence of brakingand, therefore, that free energy is available. While only a few datapoints are shown as representatives of when free energy available, awide variety of other data points may also be sampled to provide anindication.

After block 703, the controller 300 provides a command to activate ordeactivate the charging of the accumulator tank (block 704) based on atleast one of the pressure data, the accumulator tank pressure setting,and the energy data. In regard to the pressure data, the pressure datamay indicate that the pressure in the accumulator tank is at or belowthe minimum pressure setting, at or above the maximum allowed pressure,or somewhere in between. When the pressure in the tank is at or below aminimum pressure setting, the controller 300 may activate the chargingof the tank. This is because one or more components in the vehicle mayneed at least the minimum pressure in the tank to function. When thepressure is at or above the maximum allowed pressure, the controller 300deactivates the compressor to prevent over-pressurizing the tank(s).When pressure in the tank is somewhere in between the minimum andmaximum pressure or less than the minimum pressure setting, the energydata and accumulator tank pressure setting may influence the charging ofthe tank(s).

In one example configuration, the pressure in the accumulator tank issomewhere in between the minimum and maximum pressure. When thecontroller 300 determines that free energy is available based on theenergy data, the controller provides a command to activate the chargingof the accumulator tank. The controller 300 provides this command untileither the maximum allowed pressure in the tank (e.g., from pressuresensor 342, etc.) is reached or no more free energy is available,whichever occurs first. If the pressure in the tank is at the maximumallowed pressure but free energy is available, the controller 300 mayprovide a command to store this energy in one or more batteries forlater use (e.g., when the pressure in the tank drops below a minimumpressure setting).

In another example configuration, the pressure in the accumulator tankis below the minimum pressure setting (i.e., the cut-in pressure). Asdescribed above, the minimum pressure setting is the minimum amount ofpressure needed in the tanks to run one or more components in thevehicle powered by the tanks (e.g., the air brakes). Therefore, forsafety, the controller 300 may be preset to activate the charging of thetank(s) when the pressure is at or below the minimum pressure setting,regardless of the availability of free energy. Rather than commandingthe tanks to be charged to the maximum allowed pressure, the controller300 may command the tank(s) to be charged to the adjustable pressuresetting (block 702) utilizing any stored or determined available amountof free energy. Thus, in one embodiment, the adjustable tank pressuresetting may be less than the maximum allowed pressure. However, theadjustable tank pressure setting may function akin to the maximumallowed pressure. When the adjustable tank pressure setting pressure isreached in the tank, the charging of the tank is deactivated by thecontroller 300. If there is no stored or available free energy, non-freeenergy may be used to power the compressor to charge the tank to theadjustable tank pressure setting. In any event, because the adjustabletank pressure setting is less than a maximum allowed pressure setting,the energy (free or non-free) needed to charge the tank(s) is relativelysmaller. If at any time free energy becomes available, the controller300 may provide a command to utilize the free energy in place of thenon-free energy. The command may be sustained until the free energy isno longer available or the maximum allowed pressure in the tank(s) isreached (whichever occurs first). If the pressure setting (block 702) isnot reached during the use of free energy, the controller 300 mayprovide a command to continue to charge the tank until the pressuresetting is reached (thus, for that example, the energy usage is:non-free—free—non-free up to the pressure setting).

As such, in summary of the example embodiments, the controller 300 mayprovide a command to charge the tank based on the pressure data, energydata, and the accumulator tank pressure setting. Whenever free energy isavailable, the controller 300 may command charging until theavailability of free energy ceases or the maximum allowed pressure isreached, whichever occurs first. In order to conserve energy, when freeenergy is not available and the pressure is below a minimum pressuresetting, the controller 300 may command a charging of the tank to theaccumulator tank pressure setting (block 702), which is below themaximum allowed pressure of the tank. When the accumulator tank pressuresetting is reached and free energy is not available to fully charge thetank, the controller 300 may provide a command to deactivate thecompressor to reduce energy consumption (i.e., from continualoperation). Similarly, when the maximum allowed pressure is reached, thecontroller 300 may also provide a command to deactivate the compressor.Also, when the pressure data indicates the pressure to be in between theminimum and maximum pressure, the controller 300 may keep the compressoroff until the energy data indicates the availability of free energyand/or the pressure in the tank drops to at or below the minimumpressure setting.

Minimum pressure setting, maximum pressure setting, and the adjustabletank pressure setting may be completely customizable by a user via thecontroller 300 depending on the application. Similarly, use of the tankpressure setting may be activated or deactivated via the controller 300depending on the application. Accordingly, a wide variety ofcustomization may be possible with method 700 in conjunction with thecontroller 300.

As an example, method 700 may be implemented with an electric heatingventilation and air conditioning (HVAC) system of a vehicle. The cabinof the vehicle (i.e., the passenger and operator section of the vehicle)includes temperature control gauges that allow for control of the cabintemperature. Typically, a temperature sensor (e.g., thermostat) is alsoimplemented to gauge the temperature relative to a desired temperature.Utilizing method 700 and controller 300, the cabin temperature isadjusted based on the availability of free energy. For example, anoperator of the vehicle may turn the cabin heat on to a desired heatingtemperature. For a vehicle with a heater core (e.g., a radiator placedexternal to the cabin in the engine compartment near the firewall,typically near the passenger compartment), engine coolant flows throughthe engine (becoming heated) and then to the heater core when the heatis turned on. When the heater is not turned on, the coolant cyclesdirectly back around through a radiator of the vehicle and then throughthe engine again. When the heat is turned on, a blower (e.g., a fan) isalso activated that blows the heated coolant that is flowing through theheater core. The heated coolant heats the air which is pushed throughthe ventilation in a vehicle to increase the cabin temperature. Tocontrol the direction of the coolant and provide motive force (e.g.,propel the coolant around the system), one or more valves and a pump aretypically utilized.

Applying method 700 to the example above, a coolant tank or reservoirwould be analogous to the accumulator tank 140 of FIG. 2. The controllerof a vehicle, such as controller 300, receives pressure data for coolanttank (block 701). The pressure data indicates a capacity level for thetank (e.g., a level of fullness). The controller also receives energydata (block 702), which provides an indication of the availability offree energy. When free energy is available, the controller provides acommand to heat the cabin (block 704). The command may includeactivating the blower and opening one or more valves to direct theheated coolant (from the engine) to the heater core. In this situation,relative to the heating temperature desired, the controller may commandthat heat be provided until a set temperature above the heatingtemperature is achieved (e.g., ten degrees). Over time, the cabintemperature may decrease such that an average temperature of the cabinmay be closer to the heating temperature than if the heater wasdeactivated upon reaching the heating temperature. This method alsotakes advantage of the available free energy to continue to provide heatto the cabin and to activate the heating system when free energy isavailable.

In a similar application, the method 700 may be utilized with thecooling portion of the HVAC system as well. In this case, a compressor(e.g., the electric compressor of FIG. 2 that collectively refers to themotor 120 and the compressor 110) compresses and pumps refrigerantaround the cooling system (e.g., the condenser, evaporator,drier/receiver, etc.). The accumulator tank for the refrigerant may be aseparate holding vessel or may be combined with a drier/receiver in thecircuit. Here, activation of the cooling system (e.g., a compressor) iscontrolled based on the availability of free energy. When free energy isavailable, the controller activates the system. When free energy is notavailable, the controller deactivates the system. However, the operatormay utilize one or more cabin controls to override the deactivation. Inthis configuration, as in the heating configuration above, heating andcooling is controlled based on the availability of free energy.

Another example implementation of the accumulator system 100 and themethod 700 is with a hydraulic system of a vehicle. In some vehicles,hydraulic systems may provide actuation of one or more vehicle devicesusing hydraulic fluid. These vehicle devices may include, but are notlimited, hydraulic brakes, power steering, crane/boom operation, etc. Inthis case, the accumulator tank may be structured as a hydraulicaccumulator because of the use of hydraulic fluid. As compared to acompressor with the system in FIG. 2, the controller mayactivate/deactivate a mechanical or electric hydraulic pump to chargethe hydraulic accumulator when free energy is available. In doing so,the controller avoids turning the pump on in the future (when freeenergy is not available) by using the stored hydraulic pressure causedby the free energy activation of the pump.

Referring to FIG. 8, a method 800 of energy management is shownaccording to an example embodiment. The method 800 may be executed by,for example, the controller 300 and the modules thereof. At block 801,the controller 300, and more particularly the energy generation module310, determines a quantity of available energy generated from an energygeneration event. For example, at block 801, energy generation module310 may determine an event from the braking system 40 (e.g.,regenerative braking) or energy conservation (e.g., energy not beingused during coasting of a vehicle or during a vehicle idle condition).Block 801 may include receiving data from one or more sensors 340coupled to various vehicle systems for determining the event, and mayinclude the identification of if the energy is free or non-free.

At block 802, the controller 300, and more the particularly batterymodule 312, determines the available capacity of a vehicle batterysystem to determine if the energy generated during the energy generationevent may be stored via the battery. In some embodiments, there may bemore energy generated from an event (e.g., a braking event may generatemore energy than can be stored by the battery).

At block 803, the controller 300, and more particularly the comparatormodule 322, compares the quantity of energy generated during the energygeneration event to the capacity currently available at the battery. Atblock 804, the controller 300 analyzes how to store the generated energybased on the outcome of the comparison at 803. Specifically, if thequantity of energy generated via the energy generation event is lessthan or equal to the quantity of available capacity in the batterysystem, the energy generated during the energy generation event isstored in the battery (represented at block 805). However, if thequantity of energy generated via the energy generation event is greaterthan the quantity of available capacity in the battery system, it isbeneficial during this time to store energy generated during the energygeneration event.

As one example, the energy may be used in the coolant system in the formof excess cooling. During a braking event in which the batteries do notneed to be charged, the fan may be operated to lower the coolanttemperature. The operation of the fan is controlled through lowering thetarget coolant temperature of coolant contained in a heat managementsystem, such as a radiator system configured to cool the internalcombustion engine of the vehicle. Accordingly, at block 806, the energymanagement system causes the target coolant temperature for the coolantcontained in the radiator system to be lowered to control actuation ofthe cooling fan for the heat management system. The lowered targettemperature causes the fan to come on sooner than it would at thenominal coolant target temperature, thereby cooling the coolant in theheat management system to a temperature lower than the normal. Asdiscussed in the present disclosure, the target temperature may bepermitted to rise in example embodiments to conserve energy. Forexample, referring again to FIG. 6, the temperature may be permitted tofall from a temperature target 601 closer to the lower limit 603 duringthe activities of block 806. During subsequent operation of the coolantsystem, the temperature may be allowed to rise back towards temperaturetarget 601 to conserve energy.

In various other embodiments, the energy may be used or stored in otherways and in other vehicle subsystems. While the embodiment of FIG. 8shows the coolant temperature and coolant system as an example vehiclesubsystem, the method 800 may be applicable for any other vehiclesubsystem in which energy may be applied to when there is no capacity inthe battery system.

In certain embodiments, the controller 300 includes an HVAC moduleconfigured to control engagement of a compressor and/or one or morecomponents of an HVAC system in response to an energy generation event.For example, as an alternative to or in addition to lowering coolanttarget temperature to activate a cooling fan, the controller 300 mayactivate a compressor to lower a target temperature of the HVAC systemduring periods of available electrical energy capacity that exceed theenergy storage capacity of a battery system.

Referring to FIG. 9, a method 900 for prioritizing energy distributionamong vehicle subsystems is shown according to an exemplary embodiment.Process 900 may be executed by, for example, the controller 300 and moreparticularly the prioritization module 324 of FIG. 4. Process 900 maygenerally be executed as a backup control strategy, such that abrown-out condition or other critical condition with the power supply ofthe vehicle is avoided.

Process 900 includes monitoring the alternator current of the batterysystem 32 (block 902) and comparing the monitored alternator current tothe current limit of the alternator (block 904). Blocks 902, 904generally include the monitoring of the battery system 32 as a backupsystem in case the battery management system of the present disclosurefails to detect an overloaded supply for any reason. For example, ifvehicle subsystems that cannot be turned on and off by the controller300 (e.g., operator-selectable systems such as HVAC fans, headlights,window defoggers, cigarette lighters, etc.) are operated, an overloadedsupply may not be detected. Monitoring the alternator current at block902 allows for an alternative way of monitoring if the supply isoverloaded.

Process 900 further includes receiving energy data, energy storage data,and current data (block 906), along with other data. Block 906 includesobtaining data that may be useful in determining the energy generated byvarious vehicle subsystems, and the energy currently available at thebattery, as generally described in the present disclosure. Process 900further includes determining if the energy output of the battery system32 should be reduced based on the received data and the alternatorcurrent (block 908).

A prioritization structure for engine subsystems may then be determined.If the energy output of the battery system 32 should be reduced, itshould not necessarily be done uniformly, as some accessory loads may bemaintained while others are reduced. Process 900 may include, for eachengine subsystem, determining the criticality of the load (block 910).For example, engine subsystems that are critical for vehicle operation(e.g., a power steering system, etc.) should not be compromised, whileengine subsystems that are not related to general vehicle performanceare more likely candidates for load reduction. Process 900 may furtherinclude determining the means of energy storage associated with eachengine subsystem (block 912). Many subsystems may perform a functionthat represents some form of energy translation, which have a degree ofenergy storage capability. This energy storage capability may allow foroffsetting a reduced operation with an increased operation in thefuture. Process 900 then includes determining a prioritization structurefor the engine subsystems (block 914). The engine subsystems that are ofthe highest priority may maintain their load levels, while low prioritysubsystems have their loads reduced (or shut off completely).

The schematic flow chart diagrams and method schematic diagramsdescribed above are generally set forth as logical flow chart diagrams.As such, the depicted order and labeled steps are indicative ofrepresentative embodiments. Other steps, orderings and methods may beconceived that are equivalent in function, logic, or effect to one ormore steps, or portions thereof, of the methods illustrated in theschematic diagrams.

Additionally, the format and symbols employed are provided to explainthe logical steps of the schematic diagrams and are understood not tolimit the scope of the methods illustrated by the diagrams. Althoughvarious arrow types and line types may be employed in the schematicdiagrams, they are understood not to limit the scope of thecorresponding methods. Indeed, some arrows or other connectors may beused to indicate only the logical flow of a method. For instance, anarrow may indicate a waiting or monitoring period of unspecifiedduration between enumerated steps of a depicted method. Additionally,the order in which a particular method occurs may or may not strictlyadhere to the order of the corresponding steps shown. It will also benoted that each block of the block diagrams and/or flowchart diagrams,and combinations of blocks in the block diagrams and/or flowchartdiagrams, can be implemented by special purpose hardware-based systemsthat perform the specified functions or acts, or combinations of specialpurpose hardware and program code.

Many of the functional units described in this specification have beenlabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom VLSI circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A module may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Modules may also be implemented in machine-readable medium for executionby various types of processors. An identified module of executable codemay, for instance, comprise one or more physical or logical blocks ofcomputer instructions, which may, for instance, be organized as anobject, procedure, or function. Nevertheless, the executables of anidentified module need not be physically located together, but maycomprise disparate instructions stored in different locations which,when joined logically together, comprise the module and achieve thestated purpose for the module.

Indeed, a module of computer readable program code may be a singleinstruction, or many instructions, and may even be distributed overseveral different code segments, among different programs, and acrossseveral memory devices. Similarly, operational data may be identifiedand illustrated herein within modules, and may be embodied in anysuitable form and organized within any suitable type of data structure.The operational data may be collected as a single data set, or may bedistributed over different locations including over different storagedevices, and may exist, at least partially, merely as electronic signalson a system or network. Where a module or portions of a module areimplemented in machine-readable medium (or computer-readable medium),the computer readable program code may be stored and/or propagated on inone or more computer readable medium(s).

The computer readable medium may be a tangible computer readable storagemedium storing the computer readable program code. The computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples of the computer readable medium may include butare not limited to a portable computer diskette, a hard disk, a randomaccess memory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), a portable compact discread-only memory (CD-ROM), a digital versatile disc (DVD), an opticalstorage device, a magnetic storage device, a holographic storage medium,a micromechanical storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, and/or storecomputer readable program code for use by and/or in connection with aninstruction execution system, apparatus, or device.

The computer readable medium may also be a computer readable signalmedium. A computer readable signal medium may include a propagated datasignal with computer readable program code embodied therein, forexample, in baseband or as part of a carrier wave. Such a propagatedsignal may take any of a variety of forms, including, but not limitedto, electrical, electro-magnetic, magnetic, optical, or any suitablecombination thereof. A computer readable signal medium may be anycomputer readable medium that is not a computer readable storage mediumand that can communicate, propagate, or transport computer readableprogram code for use by or in connection with an instruction executionsystem, apparatus, or device. Computer readable program code embodied ona computer readable signal medium may be transmitted using anyappropriate medium, including but not limited to wireless, wireline,optical fiber cable, Radio Frequency (RF), or the like, or any suitablecombination of the foregoing.

In one embodiment, the computer readable medium may comprise acombination of one or more computer readable storage mediums and one ormore computer readable signal mediums. For example, computer readableprogram code may be both propagated as an electro-magnetic signalthrough a fiber optic cable for execution by a processor and stored onRAM storage device for execution by the processor.

Computer readable program code for carrying out operations for aspectsof the present invention may be written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Java, Smalltalk, C++ or the like and conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The computer readable program code mayexecute entirely on the user's computer, partly on the user's computer,as a stand-alone computer-readable package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server.

The program code may also be stored in a computer readable medium thatcan direct a computer, other programmable data processing apparatus, orother devices to function in a particular manner, such that theinstructions stored in the computer readable medium produce an articleof manufacture including instructions which implement the function/actspecified in the schematic flowchart diagrams and/or schematic blockdiagrams block or blocks.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Accordingly, the present disclosure may be embodied in other specificforms without departing from its spirit or essential characteristics.The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the disclosure is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A method, comprising: receiving, by a controller,pressure data for an accumulator system, the pressure data providing anindication of a pressure in an accumulator tank of the accumulatorsystem; receiving, by the controller, energy data, the energy dataindicating an availability of free energy for use to charge theaccumulator tank; and activating, by the controller, a charging sourceof the accumulator tank to charge the accumulator tank based on at leastone of the pressure data and the energy data.
 2. The method of claim 1,further comprising determining, by the controller, that free energy isavailable based on the energy data and, in response, activating thecharging source to charge the accumulator tank.
 3. The method of claim2, wherein the activation is until at least one of a maximum allowedpressure of the accumulator tank is reached and the energy dataindicates that the free energy is no longer available.
 4. The method ofclaim 1, further comprising determining, by the controller, that theaccumulator tank pressure is at or below a minimum pressure setting;determining, by the controller, that free energy is not available; andactivating, by the controller, the charging source to charge theaccumulator tank up to an accumulator tank pressure setting, wherein theaccumulator tank pressure setting is less than a maximum allowedpressure of the accumulator tank.
 5. The method of claim 1, furthercomprising determining, by the controller, that free energy isavailable; determining, by the controller, that the accumulator tankpressure is at or below a maximum allowed pressure; and activating, bythe controller, the charging source to charge the accumulator tank untilat least one of the maximum allowed pressure of the accumulator tank isreached and the energy data indicates that free energy is no longeravailable.
 6. The method of claim 1, wherein the energy data includes anindication of at least one of an accelerator pedal position, a vehiclespeed, a brake pedal position, and an engine fueling rate.
 7. A system,comprising: an accumulator system including an accumulator tank and anelectric compressor structured to charge the accumulator tank; and acontroller operatively and communicably coupled to the accumulatorsystem, the controller structured to: receive pressure data indicativeof a pressure in the accumulator tank; receive energy data indicative ofan availability of free energy to power the electric compressor tocharge the accumulator tank; and activate the electric compressor tocharge the accumulator tank based on at least one of the pressure dataand the energy data.
 8. The system of claim 7, wherein the free energyis provided by a regenerative braking system.
 9. The system of claim 7,wherein the controller is structured to determine that free energy isavailable and, in response, activate the electric compressor.
 10. Thesystem of claim 9, wherein the controller activates the electriccompressor until at least one of a maximum pressure setting of theaccumulator tank is reached and a determination by the controller thatfree energy is no longer available.
 11. The system of claim 7, whereinthe controller is structured to receive a pressure setting for theaccumulator tank.
 12. The system of claim 11, wherein the controller isstructured to determine that the accumulator tank pressure is at orbelow a minimum pressure setting, determine that free energy is notavailable, and activate the electric compressor to charge theaccumulator tank up to the pressure setting, wherein the pressuresetting is less than a maximum allowed pressure of the accumulator tank.13. The system of claim 7, wherein the controller is structured todetermine that free energy is available, determine that the accumulatortank pressure is at or below a maximum allowed pressure, and activatethe electric compressor until at least one of the maximum allowedpressure of the accumulator tank is reached and the energy dataindicates that free energy is no longer available.
 14. The system ofclaim 7, wherein the accumulator system includes a dryer operativelycoupled to a governor, wherein the dryer is structured to removemoisture from a medium compressed by the electric compressor prior tothe medium being directed to the accumulator tank, and wherein thegovernor facilitates an accumulated pressure release in at least one ofthe dryer and the accumulator tank.
 15. An apparatus, comprising: anenergy generation module operatively coupled to one or more energygeneration sources, wherein the energy module is structured to receiveenergy data indicative of an availability of free energy; and anaccumulator module communicably coupled to the energy module, whereinthe accumulator module is structured to receive pressure data indicativeof a pressure in an accumulator tank of an accumulator system andfacilitate charging the accumulator tank based on an indication of freeenergy relative to the pressure of the accumulator tank.
 16. Theapparatus of claim 15, wherein the free energy is provided by aregenerative braking system.
 17. The apparatus of claim 15, wherein theaccumulator module charges the accumulator tank until at least one of amaximum pressure setting of the accumulator tank is reached and theenergy data indicates that free energy is no longer available.
 18. Theapparatus of claim 15, wherein in response to the accumulator tankpressure being at or below a minimum pressure setting and the energygeneration module determining that free energy is not available, theaccumulator module is structured to facilitate charging the accumulatortank up to the pressure setting.
 19. The apparatus of claim 15, whereinin response to the energy generation module determining that free energyis available and the accumulator module determining that the accumulatortank pressure is at or below the maximum allowed pressure, theaccumulator module facilitates charging of the accumulator tank until atleast one of a maximum allowed pressure of the accumulator tank isreached and the energy data indicates that free energy is no longeravailable.
 20. The apparatus of claim 15, wherein the accumulator systemincludes a dryer operatively coupled to a governor, wherein the dryer isstructured to remove moisture from a medium compressed by the electriccompressor prior to the medium being directed to the accumulator tank,and wherein the governor facilitates an accumulated pressure release inat least one of the dryer and the accumulator tank.